POS1430 WATCH OUT FOR THE INFLAMMATORY RESPONSE IN AUTOIMMUNE DISEASES WITH INTERSTITIAL PNEUMONIA. A RETROSPECTIVE STUDY
Authors: F. Romero Bueno, M. J. Rodriguez, M. A. Nieto, C. Palacios Miras, I. Martín Lores, C. Vadillo, M. C. Vegas Sánchez, L. Abasolo, O. Sanchez Pernaute
Journal: Annals of the Rheumatic Diseases (2022)

Background Chronic interstitial pneumonia (IP) is often a feature of autoimmune rheumatic diseases (ARD). While potentially a life-threatening complication, it is however highly heterogeneous both as regards its presentation and its progression over time. Some patients may have a predominantly lung involvement, a context which hampers their classification and/or management. The recently coined concept of interstitial pneumonia with autoimmune features (IPAF) may help to identify these cases, albeit some others might remain unclassified (UAIP). Either with or without an overt underlying ARD, real-life data are regarded fundamental to shed light on the natural course of autoimmune IP (AIP) and to identify prognostic markers in order to tailor follow-up and therapeutic approaches Objectives To find prognostic markers in our cohort of patients with autoimmune diseases with AIP (comprising ARD-IP, IPAF and UAIP), which may guide our therapeutic strategies. Methods We set a retrospective study including all patients diagnosed with AIP from our Clinic with a minimum follow-up of 3 yr -or until death-. The end of the study was set at January 2020. We collected demographic data and classified the disease according to the updated criteria for the ARDs, Fischer’s preliminary criteria of IPAF and Solomon’s proposed criteria of anti synthetase (ARS) syndrome. We registered morphological, serological and clinical features of the disease. Besides, available laboratory parameters were recorded as dichotomous variables (absent/present; normal/increased). The dependent variable of our study was death. Student’s t, Fisher’s exact test and survival techniques were employed in the univariate analysis. Logistic regression analysis was done to assess death prediction models. One way ANOVA and Dunnett 2 sided t were employed in multi-group comparisons of means. Results A total of 118 patients (69% women), comprising 63 patients (53%) with ARD-IP, 37 (31%) with IPAF and 18 (15%) with UAIP, were included. There were 22 patients fulfilling RA criteria, 16 patients SSc criteria and 20 patients meeting criteria for IM. Twenty one patients could be diagnosed with ARS syndrome. Disease duration was not different between subgroups, with a total follow-up of 984 patient-years. Age at onset was significantly younger in ARD-IP cases (54 ± 2), than in IPAF (61,7 ± 2,7), p 0.035, and also in 2 group comparison with UAIP (72,1 ± 1,9), p &lt; 0.001, p 0.019, respectively. Thirty one deaths occurred during follow-up. In the univariate analysis, older age at presentation (difference: -11,2 ± 3,3 y.o. [CI95: -17.9; -4.6] p 0,001), a shorter course of the disease (difference: 4,5 ± 1,1 y [CI95: 2,3; 6,8] p &lt; 0.001) and the presence of pulmonary hypertension (OR 6,08 ± 1,69 [CI95 2,18; 16,96] p 0.001) were associated to fatal cases. On the other hand, none of clinical subgroups, morphological patterns or autoantibodies conveyed death risk. As regards laboratory parameters, increases of ferritin, triglycerides, ESR, CRP and LDH were strong predictors of death (Table 1). With logistic regression, the combination of older age, pulmonary hypertension, increased ferritin an increased ESR was the best model for death prediction (OR 14,57, p &lt; 0.001), while the elevation of LDH and CRP could be explained by the mentioned 4-factor model. Table 1. Laboratory parameter alive dead OR p increased ferritin 19p (22,9%) 16p (51,6%) 3,59 ± 1,56 [CI95 1,50; 8,58] 0,004 increased ESR 47p (55,3%) 24p (77,4%) 2,77 ± 1,62 [CI95 1,08; 7,13] 0,034 increased CRP 49p (57,6%) 27p (87,1%) 4,96 ± 1,78 [CI95 1,59: 15,43] 0,006 increased triglycerides 6p (7%) 7p (22,6%) 3,84 ± 1,83 [CI95 1,18: 12,53] 0,026 increased LDH 34p (40%) 23p (74,2%) 4,31 ± 1,59 [CI95 1,73; 10,76] 0,002 Conclusion According to our data, markers of macrophage activation and the activation of acute phase response could be taken as risk factors of a poor outcome in patients with AIP, regardless of clinical diagnosis and process-related features. Nonetheless, due to our study design and sample, these resutls warrant replication in other cohorts. Acknowledgements This study has been conducted with a Grant from the Carlos III Health Institute AES2020 program, Spanish Ministry for Science and Innovation (PI20/00250) Disclosure of Interests None declared